The major purpose of this Program is to provide comprehensive predoctoral training in Environmental and Molecular Toxicology coupling strong discipline-based preparation in cell and molecular biology/genetics with a case-based approach for addressing problems in environmental health sciences. Training is provided through the Graduate Program in Environmental Toxicology. Fourteen core faculty in the graduate program will serve as mentors/thesis directors for trainees. They will provide research opportunities and specific training in four areas of emphasis: (1) cellular/molecular toxicology and toxicogenomics, (2) molecular endocrinology/disruptors, (3) neuropharmacology and neurobehavioral toxicology, and (4) environmental toxicology/risk analysis. All trainees take core toxicology courses, advanced courses in cell and molecular biology, statistics and risk analysis, and elective courses in environmental toxicology. Trainees perform research in one of the featured specializations. Examples of research training include studies of genes and signaling pathways regulating drug or environmental toxin-induced cell cycle arrest, differentiation, and apoptosis in myeloid- and lymphoid-lineage cell line models; regulation of pesticide sensitivity by cytochrome P450 genes; cloning and characterization of genes encoding major insecticide target sites; molecular mechanisms of hormone action and endocrine disruptors; environmental factors and mechanisms contributing to tumor development and regression in target aquatic species. The major intent of the Program is to provide graduate students intensive academic and research training in the sub-disciplines of toxicology, but also preparation, via courses, seminars, and peer interactions, for addressing the complex issues often encountered in the environmental health sciences. Support for five (5) predoctoral trainees is requested. Trainees entering the Program have strong, well-balanced undergraduate (or graduate) backgrounds and research experiences in the basic biological, physical, and environmental sciences. Graduates of the Program are prepared to assume positions of responsibility in academia, research institutes, regulatory agencies, and the chemical/pharmaceutical industries. University support of the Environmental Toxicology Training Program is substantial with respect to research environment and facilities, computing and statistical support, extensive library system, and financial support from the Graduate School and the colleges involved in the Program.